A sputtering type Penning discharge for metallic ions

An ion source in which ions of normally solid materials are easily produced. A plasma is generated in a gas adjacent the solid material from which ions are to be produced. The solid is negatively charged and the gas plasma ions bombard the solid, sputtering off ions of the solid. This is accomplished through the use of a Penning discharge with a cold cathode-type source and a centrally positioned and negatively charged dynode upon which the solid material is mounted, the dynode being electrically connected to the cathode and provided with an exit slit through which the metallic ions are extracted from plasma potential.